Solubility of Zn and Pb in liquid iron and their partition between liquid iron and selected steelmaking slag systems

The use of Zn- and Pb-contaminated scrap in steelmaking has led to a significant increase of the zinc and lead contents in dusts and sludges, especially produced in the electric arc furnace melting shops. To understand the behaviour of Zn and Pb, fundamental research on the thermodynamics and kinetics of zinc and lead reactions under steelmaking conditions is helpful. In the first part of the present work, the solubilities of lead and zinc in iron are discussed. Furthermore, the influence of several alloying elements, such as carbon, oxygen, sulfur and chromium on the dissolution behaviour of Zn and Pb was examined and compared with former studies. Measurements of the solubility of lead in liquid iron were made at elevated temperatures in the systems Fe-Pb-O, Fe-Pb-C and Fe-Pb-Cr under argon in a gas-tight Tammann furnace. An increase of lead solubility was found with increasing temperature and increasing oxygen content. On the other hand, higher contents of carbon and chromium led to lower solubilities of lead in liquid iron. In the second part, the partition ratios of zinc and lead between liquid iron and various selected slag compositions were investigated. It is shown that zinc partition is determined by oxygen activity and slag basicity. In SiO₂-saturated slags, the partition ratio of zinc is considerably higher than in CaO-saturated slags. In comparison, the partition ratio of lead is significantly lower under the same experimental conditions.     

A Mossbauer study of electric steelmaking basic slags

Mössbauer measurements have been made on powder samples of basic slags from a steelmaking electric furnace. The samples were taken during oxygen blowing. A prevalence is found of divalent iron in “mixed oxidrd form and in the silicate phase. The ability of Mössbauer spectroscopy to characterize such heterogeneous materials and to correlate the distribution of ferrous ions between the oxide and the silicate with the composition of the slags is demonstrated.     

高炉渣对钢渣改性的物理化学基础研究

钢渣用作建筑材料时,由于其中含有大量游离氧化钙(f-CaO),稳定性较差,通常需要改性钢渣以提高其稳定性、胶凝性. 在对钢渣、高炉渣进行化学成分和矿物组成分析的基础上,对高炉渣改性钢渣的可能性进行了热力学计算,结果表明高炉渣中的SiO₂与钢渣中f-CaO反应,生成胶凝相,同时降低了钢渣中的f-CaO含量. 本文通过研究热态高炉渣改性钢渣,结合X射线衍射、拉曼光谱、扫描电镜及能谱分析等研究方法,对改性钢渣的矿物成分、f-CaO含量、黏度变化等进行了分析. 研究发现随着热态高炉渣配比量的增加,改性渣黏度缓慢增加,改性钢渣中f-CaO、RO相含量降低,改性渣的胶凝性能提高. 在1550℃下,钢渣中添加10%高炉渣时,改性渣中2CaO·SiO₂(C₂S)、3CaO·SiO₂(C₃S)含量显著提高,f-CaO质量分数降至1.64%,稳定性大大提高,符合建材化使用要求. 此外,进一步使用焦炭还原改性渣中的铁,轻松实现了渣铁分离,提高改性渣的易磨性.      

Determination of Physical and Chemical Properties of Electric Arc Furnace Dusts for the Purposes of Their Utilization

Electric arc furnace dusts are among the most environment polluting wastes. Numerous utilization technologies have been developed for dusts containing up to 4% of Zn and more than 20% of Zn. However, the remaining part of steelmaking dusts are the most problematic ones, as they are mostly dumped generating costs and posing serious environmental threats. This paper provides an analysis of the potential utilization options for dusts containing ca. 10% of zinc generated in a single electric steelmaking shop. Physical and chemical properties of dusts have been determined and examined, and furthermore, results of the studies on the EAFD utilization in production of cement clinker and industrial glass have been discussed. It has been found that a particularly beneficial feature of the production technology proposed is that the iron content exceeds 30%. The influence of the dusts used on the functional properties of the products obtained has been established as well as the environmental impact of the processes and products in question and the dust mass possible to be utilized in the production technology proposed have been determined.     

Role of prereduced pellets in the slag foaming in modern EAFs

The problems of electric arc furnace slags are considered, and the role of prereduced pellets in the slag foaming in electric arc furnaces is studied. The optimum rate of loading of prereduced pellets into a furnace that ensures effective steelmaking slag foaming is determined as a function of the degree of pellet prereduction.     

Recovering and recycling scrap from dumps containing steelmaking slags

The company Mittal Stil Temirtau has accumulated more than 13 million tons of steelmaking slag, and it annually adds another 600,000 tons of slag to this amount from ongoing production operations. Here, some of the iron from the production process is lost in the form of metallic iron and oxides. The total amount of iron lost is estimated to be 15%. Studies have established that discarded steelmaking slags contain up to 8% magnetic products. A slag-processing unit began operation at the dump in 2003 to recover scrap from the slag. The unit has a productivity of 120 tons of bank slag per hour and can process slag with an initial coarseness of up to 700 mm. Extracting iron-bearing products from steelmaking slags and returning them to the production cycle has reduced iron losses by 30% for the metallurgical conversion as a whole. __________ Translated from Metallurg, No. 1, pp. 80–81, January, 2006.     

电弧炉用替代废钢的金属炉料的进展

直接还原铁、铁水、冷生铁、脱碳粒铁、碳化铁、复合金属料等替代部分废钢作为电弧炉金属炉料，不仅可解决目前废钢供应短缺，也有利于稀释废钢中有害残余元素，提高钢的质量，是电弧炉冶炼优质钢的必要条件。文中介绍了电弧炉用各种金属炉料的特点和使用效果。     

Theoretical analysis of the interfacial phenomena during the injection of carbon particles into EAF slags

A theoretical analysis of FeO reduction through the injection of carbon fines in electric arc furnace slags, involving the interfacial phenomena at the liquid‐gas‐solid interface, has been performed using basic principles of transport phenomena and physical chemistry of steelmaking. It was found that small angle contacts between slag and carbon favour FeO reduction. Moreover, FeO in basic slags are more prone to be reduced because the interfacial liquid‐gas interface has more free reaction places. In acid slags FeO reduction is difficult because the gas‐liquid interface is partially filled by polymeric silicates. When the particle size is smaller than 100 μm the influence of slag basicity is considerably decreased. Practical applications of these results can be found in electric arc furnace shops aiming at the mastering of slag foaming practices and energy saving.     

Process dynamics of electric arc furnace during direct reduced iron melting

A phenomenological mathematical model to simulate steelmaking operations in an electric arc furnace (EAF) has been developed. This model has been validated with industrial data from a Mexican company that employs direct reduced iron (DRI) as the main iron unit. The slag and steel composition can be predicted in real time with the aid of several components integrated into the simulator. The model starts with the optimization of mass and energy balances that yields the requirement of materials to produce a given quality of steel with the minimum cost. The rate of reduction of iron oxide is computed based on two reactions occurring between the FeO and carbon dissolved in the metal and FeO with the carbon particles injected into the slag. A mechanism of consumption of carbon particles has been completed, which includes the effect of surfactant species in the slag and operational variables of the industrial practice of carbon injection. A new concept, called dynamic foaming index, (DFI) is proposed to quantify the actual foaming behavior of industrial slags throughout a commercial heat. The results prove the versatility and robustness of the present mathematical model and provide a knowledge base to assist in the design, operation, and optimization of metallurgical practices for EAF steelmaking.     

Recent Development in Slag Treatment and Dust Recycling

Slags from metallurgical processes are widely used in different fields of application, e.g. in the building industry and as fertilisers. Nevertheless, also these by‐products have to be improved to ensure their sustainable use. The treatment of liquid slags, e.g. by changing their composition outside of the steel production process, will lead to interesting new properties of the newly formed products and thus guarantee their use in the future. Moreover, dust and sludges from off‐gas cleaning of metallurgical processes are becoming promising resource for coating and alloying elements. The very important element Zn for surface coating is enriched in the dusts, due to the recycling of Zn coated scrap. On the other hand, Zn might run short in the future, so that recovering of Zn from dusts and sludges may become necessary. To improve the efficiency of Zn recovery a dust re‐cycling process has been developed for EAF steelmaking by FEhS‐Institute. Some interesting side effects are supported by the dust recycling. It has been proved that the slag foaming can be enhanced by dust recycling, even for stainless steelmaking processes. Finally it can be shown that recovery of valuable elements from residues of iron and steelmaking is becoming more and more important. New developed processes are ready to be implemented into the daily steelmaking practise.     

狠抓直接还原铁质量

直接还原过程中矿石的脉石转入DRI,给电炉冶炼带来一系列影响.直接还原铁质量,必须兼顾直接还原生产和电炉炼钢两个生产环节.     

电炉炼钢钢铁原料的现状分析与展望

 电炉炼钢作为短流程的核心工艺,具有铁元素循环利用率高、能源消耗低及环境效益良好的特点,推动电炉炼钢健康发展符合中国实现“碳达峰”、“碳中和”目标对钢铁绿色发展的要求。电炉炼钢入炉的钢铁原料种类较转炉多且结构灵活,并且对电炉冶炼的工艺过程控制有直接的影响。为创造充分挖掘和发挥电炉炼钢优势的良好起始条件,针对目前电炉炼钢的主要入炉钢铁原料的情况和特点,从其生产储备、工艺过程操作、能源消耗、环境保护等方面入手,分析了废钢、铁水和直接还原铁作为主要原料的使用现状及优缺点,并着重对比分析了直接还原球团特点和技术指标,为探究和优化合理的电炉炼钢入炉钢铁原料结构提供了理论依据。从资源消耗、环境保护等方面考虑,废钢和直接还原球团将成为今后短流程炼钢的主要原料。结合钢铁循环利用技术和产业专业化的逐渐成熟,以及更加绿色环保的氢冶金技术的发展,废钢综合回收利用技术、高品位洁净球团生产技术、氢气竖炉直接还原技术将会是未来电炉入炉钢铁原料生产技术的发展方向,配套新型高效智能电弧炉冶炼技术将会是未来短流程炼钢的发展方向。     

从炼钢渣中回收铁的新方法

本文的主要目的是探索一种可持续的方法,回收钢渣中有价值的成分再利用.根据对钢渣回收利用的创新原理,使用热解重量分析法在1623～1823 K的温度范围内,在不同的气氛中对液态渣中的氧化亚铁氧化进行了实验研究.本实验中采用合成剂(二元和三元渣系)和工业炼钢渣,使用X射线衍射法进行反应产物的分析,并确认了通过氧化可将炼钢渣...     

当今最先进的镍冶炼技术——奥托昆普直接镍熔炼工艺

对近十几年的奥托昆普直接镍熔炼（DON-Direct Outokumpu Nickel）方法的作业经验（包括对环境的显著影响）进行了回顾。在DON工艺中,闪速熔炼炉中直接产出含铁低的高品位冰镍,不需要进一步吹炼。熔炼炉渣中的有价金属在电炉中以含铁冰镍回收。DON炉中产出的低熔点高品位冰镍（尤其是那些含铜低的）,对炉子设计提出了挑战,特别是对炉膛和热工的设计。参考产出的冰镍,对DON工艺、电炉冰镍及高氧化镁炉渣的热力学模型的选择结果进行了总结,对闪速炉和电炉的设计原则也进行讨论。     

用甲醇生产直接还原铁的可行性探讨

钢铁工业的调整离不开电炉炼钢的发展,而直接还原铁又是电炉炼钢发展的关键,气基竖炉生产直接还原铁在中国是短板,缺乏煤制气-竖炉技术和天然气资源。提出了一项新的还原工艺"一种利用甲醇裂解生产直接还原铁的设备及工艺",阐述了甲醇在新工艺中所体现的优点,并从使用国内煤制甲醇和进口甲醇两方面分析了甲醇作为还原剂的可行性。分析认为,从未来的发展趋势看,用甲醇生产直接还原铁的新工艺具有环保、节能、流程短等明显优势,不需要煤制气-竖炉复杂的衔接工艺,解决了还原剂的来源问题,是值得推广和发展的新思路。     

钢铁渣的农业资源化利用

钢铁渣是钢铁冶金生产的主要固体废弃物,开发冶金炉渣的综合利用技术对于防止环境污染和促进冶金工业的长期可持续发展有十分重要的意义.钢铁渣的理化特性进行了简要的介绍,详细论述了其在农业生产上的资源化再利用技术以及施用钢铁渣肥料后的土壤环境效应.钢铁渣应用于农业生产可以使其含有的有益元素得到充分利用,不会对农产品及土壤环境造成危害,而且通过在钢铁渣中加入添加剂合成新型农业肥料可以有效地提高钢铁渣肥料的附加值,更好地满足农业生产的高产和优质的需求.     

电炉煤氧喷吹的技术改造及工艺改进

简要介绍了国内第一套电炉煤氧喷吹强化电炉冶炼生产线的设备改造及工艺改进情况，使唐钢电炉钢冶炼电耗实现了“破五进四”的奋斗目标，达到４８４ｋｗｈ／ｔ的同类炉型国内先进水平，取得了较好的经济效益。     

Activity of lime in steelmaking slags

Slag samples were collected during steelmaking in a 70‐t UHP electric arc furnace charged with DRI and scrap. The proportion of DRI in the charge was varied between about 40 and 95%. The analyses of the samples were used to estimate the activity coefficient and activity of lime in the slag. Because of low concentration of P₂O₅ in these slags, published analyses of basic open‐hearth slags were utilized to investigate the effect of P₂O₅ on both activity coefficient and activity of lime. The activity coefficients and activities were correlated with the basicity and temperature. In addition, the activities were also correlated with the total lime content of the slags. The results obtained show that both activity coefficient and activity increase with increasing basicity as well as with growing temperature. While the effect of MnO on the correlation results is negligibly small, high P₂O₅ contents of basic open‐hearth slags should be considered in the calculation of the basi‐city in order to improve the correlation results. Marginal linear correlation exists between activity and content of lime in electric arc furnace slags; basic open‐hearth slags, however, give only weak linear correlation.     

100t电炉炼钢添加海绵铁的生产试验

以安钢100t电炉炼钢添加海绵铁的生产试验为依据,对海绵铁的性能及其与电弧炉冶炼过程中的关系作了全面论述,在电炉炼钢过程中添加海绵铁是降低炼钢成本、减低电炉钢水中有害残余元素含量、提高钢水纯净度、生产特殊钢的重要途径。     

钢铁行业碳减排技术应用与展望

论述了中国钢铁行业推行碳减排技术的重要意义,从多角度阐述了钢铁行业各类高效碳减排技术在国内外的应用情况及效果。首先分析了短流程炼钢工艺电弧炉炉容大型化趋势、烟气余热回收技术、废钢预热工艺和废钢供应情况;然后分别剖析了高炉富氢冶炼、富氢-气基竖炉和纯氢-气基竖炉工艺3个主要的氢冶炼工艺;之后介绍了碳捕集、利用与封存技术。最后,结合中国钢铁企业现状,展望了钢铁行业在大力推进直接还原铁技术和短流程炼钢生产工艺的情况下,未来高品质钢材低碳化、绿色化冶炼的发展之路。